blocks|key|812705|text|任务是在ThreadPool上执行的(至少，如果您使用的是默认工厂)，因此中止线程不会影响任务。有关中止任务的信息，请参阅msdn上的Task+Cancellation。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|812706|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/dd997396.aspx^0|1V|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Task are being executed on the ThreadPool (at least, if you are using the default factory), so aborting the thread cannot affect the tasks. For aborting tasks, see <a href="http://msdn.microsoft.com/en-us/library/dd997396.aspx" rel="nofollow">Task Cancellation</a> on msdn.

blocks|key|812767|text|不能。任务使用线程池中的后台线程。此外，不建议使用Abort方法取消线程。您可以查看following+blog+post，它解释了使用取消令牌取消任务的正确方法。下面是一个例子：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|812768|class+Program
{
++++static+void+Main()
++++{
++++++++var+ts+=+new+CancellationTokenSource();
++++++++CancellationToken+ct+=+ts.Token;
++++++++Task.Factory.StartNew(()+=>
++++++++{
++++++++++++while+(true)
++++++++++++{
++++++++++++++++//+do+some+heavy+work+here
++++++++++++++++Thread.Sleep(100);
++++++++++++++++if+(ct.IsCancellationRequested)
++++++++++++++++{
++++++++++++++++++++//+another+thread+decided+to+cancel
++++++++++++++++++++Console.WriteLine("task+canceled");
++++++++++++++++++++break;
++++++++++++++++}
++++++++++++}
++++++++},+ct);

++++++++//+Simulate+waiting+3s+for+the+task+to+complete
++++++++Thread.Sleep(3000);

++++++++//+Can't+wait+anymore+=>+cancel+this+task+
++++++++ts.Cancel();
++++++++Console.ReadLine();
++++}
}|code-block|syntax|javascript|812769|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.msdn.com/b/csharpfaq/archive/2010/07/19/parallel-programming-task-cancellation.aspx^0|16|J|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

You can't. Tasks use background threads from the thread pool. Also canceling threads using the Abort method is not recommended. You may take a look at the <a href="http://blogs.msdn.com/b/csharpfaq/archive/2010/07/19/parallel-programming-task-cancellation.aspx" rel="noreferrer">following blog post</a> which explains a proper way of canceling tasks using cancellation tokens. Here's an example:

<pre><code>class Program
{
 static void Main()
 {
 var ts = new CancellationTokenSource();
 CancellationToken ct = ts.Token;
 Task.Factory.StartNew(() =&gt;
 {
 while (true)
 {
 // do some heavy work here
 Thread.Sleep(100);
 if (ct.IsCancellationRequested)
 {
 // another thread decided to cancel
 Console.WriteLine("task canceled");
 break;
 }
 }
 }, ct);

 // Simulate waiting 3s for the task to complete
 Thread.Sleep(3000);

 // Can't wait anymore =&gt; cancel this task 
 ts.Cancel();
 Console.ReadLine();
 }
}
</code></pre>

blocks|key|812802|text|任务通过cancellation+tokens提供一流的取消支持。使用取消令牌创建任务，并通过取消令牌显式取消任务。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|812803|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/dd997396.aspx^0|4|J|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Tasks have first class support for cancellation via <a href="http://msdn.microsoft.com/en-us/library/dd997396.aspx" rel="nofollow">cancellation tokens</a>. Create your tasks with cancellation tokens, and cancel the tasks via these explicitly.

blocks|key|1027700|text|您可以使用CancellationToken来控制是否取消任务。你是在说在它开始之前中止它(“没关系，我已经这么做了”)，还是在中途中断它？如果是前者，CancellationToken可能会有所帮助；如果是后者，您可能需要实现自己的“保释”机制，并在任务执行的适当时刻检查是否应该快速失败(您仍然可以使用CancellationToken来帮助您，但这需要更多的手动操作)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1027701|MSDN有一篇关于取消任务的文章：http://msdn.microsoft.com/en-us/library/dd997396.aspx|1027702|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/dd997396.aspx^0|5|H|24|H|0|H|1H|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@$9|V|A|W|1|X]]|E|$]]|$1|H|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

You can use a <code>CancellationToken</code> to control whether the task gets cancelled. Are you talking about aborting it before it's started ("nevermind, I already did this"), or actually interrupting it in middle? If the former, the <code>CancellationToken</code> can be helpful; if the latter, you will probably need to implement your own "bail out" mechanism and check at appropriate points in the task execution whether you should fail fast (you can still use the CancellationToken to help you, but it's a little more manual).

MSDN has an article about cancelling Tasks:
<a href="http://msdn.microsoft.com/en-us/library/dd997396.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/dd997396.aspx</a>

blocks|key|812916|text|如果捕获在其中运行任务的线程，则很容易中止任务。以下是演示这一点的示例代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|812917|void+Main()
{
++++Thread+thread+=+null;

++++Task+t+=+Task.Run(()+=>+
++++{
++++++++//Capture+the+thread
++++++++thread+=+Thread.CurrentThread;

++++++++//Simulate+work+(usually+from+3rd+party+code)
++++++++Thread.Sleep(1000);

++++++++//If+you+comment+out+thread.Abort(),+then+this+will+be+displayed
++++++++Console.WriteLine("Task+finished!");
++++});

++++//This+is+needed+in+the+example+to+avoid+thread+being+still+NULL
++++Thread.Sleep(10);

++++//Cancel+the+task+by+aborting+the+thread
++++thread.Abort();
}|code-block|syntax|javascript|812918|我使用Task.Run()展示了最常见的用例-使用任务的舒适与旧的单线程代码，它不使用CancellationTokenSource类来确定是否应该取消它。|812919|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Aborting a Task is easily possible if you capture the thread in which the task is running in. Here is an example code to demonstrate this:

<pre><code>void Main()
{
 Thread thread = null;

 Task t = Task.Run(() =&gt; 
 {
 //Capture the thread
 thread = Thread.CurrentThread;

 //Simulate work (usually from 3rd party code)
 Thread.Sleep(1000);

 //If you comment out thread.Abort(), then this will be displayed
 Console.WriteLine("Task finished!");
 });

 //This is needed in the example to avoid thread being still NULL
 Thread.Sleep(10);

 //Cancel the task by aborting the thread
 thread.Abort();
}
</code></pre>

I used Task.Run() to show the most common use-case for this - using the comfort of Tasks with old single-threaded code, which does not use the CancellationTokenSource class to determine if it should be canceled or not.

blocks|key|812972|text|就像this+post建议的那样，这可以通过以下方式完成：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|812973|int+Foo(CancellationToken token)
{
++++Thread t = Thread.CurrentThread;
++++using (token.Register(t.Abort))
++++{
++++++++// compute-bound work here
++++}
}|code-block|syntax|javascript|812974|虽然它可以工作，但不推荐使用这种方法。如果你能控制在任务中执行的代码，你最好去适当地处理取消。|812975|entityMap|0|LINK|mutability|MUTABLE|url|http://social.msdn.microsoft.com/Forums/vstudio/en-US/d0bcb415-fb1e-42e4-90f8-c43a088537fb/aborting-a-long-running-task-in-tpl?forum=parallelextensions^0|2|9|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

Like <a href="http://social.msdn.microsoft.com/Forums/vstudio/en-US/d0bcb415-fb1e-42e4-90f8-c43a088537fb/aborting-a-long-running-task-in-tpl?forum=parallelextensions">this post</a> suggests, this can be done in the following way:

<pre><code>int Foo(CancellationToken token)
{
 Thread t = Thread.CurrentThread;
 using (token.Register(t.Abort))
 {
 // compute-bound work here
 }
}
</code></pre>

Although it works, it's not recommended to use such approach. If you can control the code that executes in task, you'd better go with proper handling of cancellation.

blocks|key|1027867|text|为了回答Prerak+K关于在Task.Factory.StartNew()中不使用匿名方法时如何使用CancellationTokens的问题，可以将CancellationToken作为参数传递给以StartNew()开始的方法，如here示例所示。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1027868|例如：|1027869|var+tokenSource+=+new+CancellationTokenSource();
var+token+=+tokenSource.Token;

Task.Factory.StartNew(+()+=>+DoSomeWork(1,+token),+token);

static+void+DoSomeWork(int+taskNum,+CancellationToken+ct)
{
++++//+Do+work+here,+checking+and+acting+on+ct.IsCancellationRequested+where+applicable,+

}|code-block|syntax|javascript|1027870|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/dd537607.aspx^0|3A|4|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

To answer Prerak K's question about how to use CancellationTokens when not using an anonymous method in Task.Factory.StartNew(), you pass the CancellationToken as a parameter into the method you're starting with StartNew(), as shown in the MSDN example <a href="http://msdn.microsoft.com/en-us/library/dd537607.aspx" rel="noreferrer">here</a>.

e.g.

<pre><code>var tokenSource = new CancellationTokenSource();
var token = tokenSource.Token;

Task.Factory.StartNew( () =&gt; DoSomeWork(1, token), token);

static void DoSomeWork(int taskNum, CancellationToken ct)
{
 // Do work here, checking and acting on ct.IsCancellationRequested where applicable, 

}
</code></pre>

blocks|key|1027929|text|我试过CancellationTokenSource，但我不能这么做。我确实用自己的方式做到了这一点。而且它是有效的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1027930|namespace+Blokick.Provider
{
++++public+class+SignalRConnectProvider
++++{
++++++++public+SignalRConnectProvider()
++++++++{
++++++++}

++++++++public+bool+IsStopRequested+{+get;+set;+}+=+false;+//1-)This+is+important+and+default+`false`.

++++++++public+async+Task<string>+ConnectTab()
++++++++{
++++++++++++string+messageText+=+"";
++++++++++++for+(int+count+=+1;+count+<+20;+count%2B%2B)
++++++++++++{
++++++++++++++++if+(count+==+1)
++++++++++++++++{
++++++++++++++++//Do+stuff.
++++++++++++++++}

++++++++++++++++try
++++++++++++++++{
++++++++++++++++//Do+stuff.
++++++++++++++++}
++++++++++++++++catch+(Exception+ex)
++++++++++++++++{
++++++++++++++++//Do+stuff.
++++++++++++++++}
++++++++++++++++if+(IsStopRequested)+//3-)This+is+important.+The+control+of+the+task+stopping+request.+Must+be+true+and+in+inside.
++++++++++++++++{
++++++++++++++++++++return+messageText+=+"Task+stopped.";+//4-)+And+so+return+and+exit+the+code+and+task.
++++++++++++++++}
++++++++++++++++if+(Connected)
++++++++++++++++{
++++++++++++++++//Do+stuff.
++++++++++++++++}
++++++++++++++++if+(count+==+19)
++++++++++++++++{
++++++++++++++++//Do+stuff.
++++++++++++++++}
++++++++++++}
++++++++++++return+messageText;
++++++++}
++++}
}|code-block|syntax|javascript|1027931|调用该方法的另一个类：|1027932|namespace+Blokick.Views
{
++++[XamlCompilation(XamlCompilationOptions.Compile)]
++++public+partial+class+MessagePerson+:+ContentPage
++++{
++++++++SignalRConnectProvider+signalR+=+new+SignalRConnectProvider();

++++++++public+MessagePerson()
++++++++{
++++++++++++InitializeComponent();

++++++++++++signalR.IsStopRequested+=+true;+//+2-)+And+this.+Make+true+if+running+the+task+and+go+inside+if+statement+of+the+IsStopRequested+property.

++++++++++++if+(signalR.ChatHubProxy+!=+null)
++++++++++++{
+++++++++++++++++signalR.Disconnect();
++++++++++++}

++++++++++++LoadSignalRMessage();
++++++++}
++++}
}|1027933|entityMap^0|3|N|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

I tried <code>CancellationTokenSource</code> but i can't do this. And i did do this with my own way. And it works.

<pre><code>namespace Blokick.Provider
{
 public class SignalRConnectProvider
 {
 public SignalRConnectProvider()
 {
 }

 public bool IsStopRequested { get; set; } = false; //1-)This is important and default `false`.

 public async Task&lt;string&gt; ConnectTab()
 {
 string messageText = "";
 for (int count = 1; count &lt; 20; count++)
 {
 if (count == 1)
 {
 //Do stuff.
 }

 try
 {
 //Do stuff.
 }
 catch (Exception ex)
 {
 //Do stuff.
 }
 if (IsStopRequested) //3-)This is important. The control of the task stopping request. Must be true and in inside.
 {
 return messageText = "Task stopped."; //4-) And so return and exit the code and task.
 }
 if (Connected)
 {
 //Do stuff.
 }
 if (count == 19)
 {
 //Do stuff.
 }
 }
 return messageText;
 }
 }
}
</code></pre>

And another class of the calling the method:

<pre><code>namespace Blokick.Views
{
 [XamlCompilation(XamlCompilationOptions.Compile)]
 public partial class MessagePerson : ContentPage
 {
 SignalRConnectProvider signalR = new SignalRConnectProvider();

 public MessagePerson()
 {
 InitializeComponent();

 signalR.IsStopRequested = true; // 2-) And this. Make true if running the task and go inside if statement of the IsStopRequested property.

 if (signalR.ChatHubProxy != null)
 {
 signalR.Disconnect();
 }

 LoadSignalRMessage();
 }
 }
}
</code></pre>

In a thread, I create some <code>System.Threading.Task</code> and start each task.

When I do a <code>.Abort()</code> to kill the thread, the tasks are not aborted.

How can I transmit the <code>.Abort()</code> to my tasks ?

How do I abort/cancel TPL Tasks?

在线程中，我创建一些System.Threading.Task并启动每个任务。当我执行.Abort()来终止线程时，任务不会中止。如何将.Abort()传输到我的任务？

问如何中止/取消TPL任务？
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何中止/取消TPL任务？EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何中止/取消TPL任务？
EN